Stem locking mechanism for electric calendar watches

ABSTRACT

A stem mechanism for an electric calendar watch with provision for rapid advancement of the date ring when the stem is in one axial position and for conventional setting of the hands of the watch when the stem is in another axial position. The stem mechanism includes a key lock for preventing inadvertent rotation of the stem in one direction and a cooperating cam for allowing stem rotation in the other direction to advance the date when desired.

United States Patent 1191 1111 3,866,407

Wuthrich Feb. 18, I975 1 STEM LOCKING MECHANISM FOR 3.762.153 10/1973 Komiyama et al 58/63 x ELECTRIC CALENDAR WATCHES [75] Inventor: Paul Wuthrich, Watertown, Conn. Primary Miller,

[73] Assignee: Timex Corporation, Waterbury,

Conn. [57] ABSTRACT [22 Filed: P 25, 1974 A stem mechanism for an electric calendar watch with Appl. No.: 463,947

US. Cl 58/58. 58/63 Int. Cl G04b 19/24, G04b 27/02 Field of Search 58/58. 63. 67, 8575 References Cited UNITED STATES PATENTS Rogers 1. 58/58 provision for rapid advancement of the date ring when the stem is in one axial position and for conventional setting of the hands of the watch when the stem is in another axial position. The stem mechanism includes a key lock for preventing inadvertent rotation of the stem in one direction and a cooperating cam for allowing stem rotation in the other direction to advance the date when desired.

1 3 Claims, 7 Drawing Figures PATENTED FEB 1 8 5 SHEET 2 OF 4 STEM LOCKING MECHANISM FOR ELECTRIC CALENDAR WATCHES BACKGROUND OF THE INVENTION This invention relates generally to electric horological devices including calendar indicating rings for the day and/or date. More particularly, it relates to electric calendar watches with provision for rapid advancement of the calendar indicating ring and is especially directed to a stem locking mechanism for preventing inadvertent actuation of the rapid advancing mechanism.

Watches are known where the day and/or date are indicated on rings which are automatically advanced from one position to the next. Watches are also known with provisions for rapid advancement of the calendar ring, and also for rapid advancement of a date ring with respect to a day ring to account for months having less than 31 days, without disturbing the timekeeping of the hands. Exemplary of the prior art are US. Pat. No. 3,360,922-Rogers issued Jan. 2, 1968; US. Pat. No. 3,421,311-Bennett, et al., issued Jan. 14, 1969; US. Pat. No. 3,439,493Mutter, et al., issued Apr. 22, 1969', US. Pat. No. 3,75l,90lMeitinger, et al., issued Aug. 14, 1973; and US. Pat. No. 3,775,965-Besson, et al., issued Dec. 4, 1973.

In the case of an electric watch, the stem does not provide the usual winding function as in a mechanical watch, and it is convenient to employ a stem which can be rotated in one axial position for setting the hands to the correct time and in another axial position to cause rapid advancement of the calendar ring. However, a problem has been experienced in the prior art whereby inadvertent rotation of the stem in the latter position can cause undesired rapid advancement ofthe calendar ring. The aforementioned US. Pat. No. 3,360,922 to Rogers seeks to solve this problem by a stem mechanism with three selectable axial positions, the rapid advancing or intermediate position serving to disengage a combination detent and calendar ring drive so that a separate rapid advancing drive mechanism can be actuated. The mechanism is fairly complicated and the operator must choose between three axial operating positions of the stem. Also exemplary of this general problem is US. Pat. No. 3,775,966-Matsuura issued Dec. 4, 1973.

Since the present invention includes as one feature thereof a key lock and cam to prevent inadvertent rotation until desired, it is acknowledged that similar devices exist in other fields, US. Pat. No. 2,917,942Jarrett, et al., being merely exemplary of many similar devices.

SUMMARY OF THE INVENTION Briefly stated, the invention comprises a stem mechanism for a horological device, especially an electric watch, with a calendar ring having provision for normal advancement and for rapid advancement via the stem mechanism. The stem is rotatable in a first axial position to set the time and is locked in a second axial position by means of a key lock in a stern bracket with means for spring loading the stem into this position. A cam cooperating with the key lock forces movement to an intermediate axial position for rapid advancement of the calendar, the stem being forced back to the locked position after rotation of the calendar ring by one increment.

Accordingly, the object of the present invention is to provide a stern mechanism for an electric. calendar watch which locks the stem against the inadvertent actuation of the rapid advance mechanism and which is economical to manufacture.

DRAWING Other objects and advantages of the invention will be made apparent by reference to the following description, taken in connection with the accompanying drawing, in which:

FIG. 1 is a partial plan view illustrating the stem locking mechanism for a day/date electric watch, showing the stem in its locked position,

FIG. 2 is an elevation drawing, taken along line 2-2 of FIG. 1 in an intermediate or calendar advancing position,

FIG. 3 is an enlarged detail view of the stem bracket showing the lock,

FIG. 4 is a corresponding enlarged elevation similar to FIG. 3,

FIGS. 5a and 5b illustrate the action of the cam, and FIG. 6 is an end view of the key lock and date change disk.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. I of the drawing, only such portions of the electric calendar watch mechanism are shown as are necessary for an understanding of the present invention. An electric calendar watch I includes a stem 2 which is rotatable and which is also moveable in an axial direction, both by means ofa conventional crown 3. The watch includes conventional time indicating hands driven by means of a suitable battery-powered indexing mechanism and synchronized or regulated by conventional means. The hands are interconnected with a ring gear, a portion of which is shown at 4, which, when rotated will rotate the hands for setting the time. The watch also includes a rotatable date ring 5 and, if desired, may also include a separately rotatable day ring 6. Although the invention is particularly illustrated with respect to rapid advancement of the date ring, it could be equally well employed for the day ring by suitable modification and hereinafter these separate rings will be referred to generically as calendar rings.

The date ring 5 includes indexing teeth 5a on its outer periphery. Index teeth 5a are used for normal advancement of the date ring by a conventional advancing mechanism (not shown) and held in place when not being rotated by a spring detent (not shown). The type of advancing mechanism and detenting mechanism used during normal time advancement of the date ring 5 is immaterial to the present invention and a large number of types are known in the art.

Rapid advancement of the date ring 5 in accordance with the present invention is provided for by means of a date setting member 7 connected to stem 2. Member 7 is a sheet metal washer with arms terminating in diametrically opposed tabs 8. Rotation of member 7 onehalf revolution causes tabs 8 to engage teeth 5a to advance date ring by one day to the next detenting position.

Reference to FIG. 2 of the drawing shows further details of the stem mechanism, in this case, when the stem has been rotated into the rapid advancing position and also shifted axially from its locking position as will be amplified later in greater detail. The watch includes conventional casing back 9, bezel 10, crystal 11, movement assembly 12, and dial 13 with windows 13a, 13b for viewing the day and date respectively.

The details of connection between the date setting member 7 and stem 2 are as follows. A bushing 14 is connected to the inner periphery of member 7 and permits axial sliding ofa cylindrical section 15 on the stem. Protrusions 16 on the stem cooperate with tabs 17 on the member 7 so that the stem can slide in the bushing. Protrusions 16 and tabs 17 together act as a coupling which causes member 7, bushing 14 and stem 2 all to rotate together when the stem is in the axial position B shown in FIG. 2. However withdrawal of the stem to an outer axial position C causes protrusions 16 to slip past tabs 17 so that when the stem is rotated to set the time, the bushing 14 and date setting member 7 are not rotated.

The bushing 14 includes diametrically opposed detenting cams 18 which are oriented to cooperate with a spring (not shown) so that the tabs 8 on the date setting member 7 normally are oriented as shown in FIG. 1 rather than as shown in FIG. 2, so that they will not interfere with the normal calendar advancing mechanism.

Returning to FIG. 1 of the drawing the stem includes opposed sloping faces 20, 21 which cooperate with a fixed stem bracket 22. The latter has opposed flexible spring arms 23 which act on sloping face to normally hold the stem in a position indicated herein as A which is a normal run position for the watch and which also corresponds to locked position hereinafter to be described. The stem also includes a time setting pinion 24 which, when the stem is withdrawn axially to another axial position C cooperates with the crown teeth 4 on the minute wheel so that the hands can be set. Movement to position C is enabled by the flexibility of arms 23 on the stem bracket.

The end of the stem may also engage the end of a lever 25 for the purpose of arresting the balance wheel when the stem is pulled into position C.

In accordance with the present invention, the stem also includes a key lock 26 and the stem bracket includes a cooperating lock and cam aperture 27. Elements 26, 27 cooperate to lock the stem against rotation in one direction and to force it to move axially against stem bracket arms 23 to an intermediate position B, so as to enable the stem to rotate 180 to advance the date ring 5 by one number and then to return back to the locked position A. The means by which this is accomplished will be made more clear by reference to the enlarged views FIG. 3 and FIG. 4 of the drawing.

FIG. 3 shows that the stem cross section is made to include a key lock section 30. The flat base 34 of stem bracket 22 is correspondingly formed with an irregular aperture 31 in the shape of a key hole, which locks the key against rotation. At diametrically opposed corners of the key hole slot, tabs 32 are struck down in opposite directions to provide inclined cam surfaces on an angle of around 45. These cam surfaces 32 cause the key portion 30 when rotated in one direction to ride up out of the key hole slot 31 so that the stem moves axially (as indicated by the change of position of pinion 24) from an axial position A to an intermediate axial position B. Reference to FIG. 2 of the drawing will also indicate the stem when it is in intermediate position B.

FIGS.' 5a and 5b further illustrate the operation. When the stem is turned in the direction of the arrow in FIG. 5a, it is forced out of the key hole slot to the in termediate axial position shown in FIG. 5b. However the stem cannot be turned in the other direction unless it is actually pulled in an axial direction out of the key hole slot.

FIG. 6 shows the relative position of the key lock and the tabs 8 on the date setting member 7. Normally the latter is inactive and in the horizontal position shown, so as not to interfere with the normal advancement of the date ring 5. However in the intermediate stem position B the member 7 rotates in the direction indicated by the arrow for one-half revolution to advance the date ring.

OPERATION Withdrawing the stem by means of the crown to a first or outer axial position C causes the stem pinion 24 to engage teeth 4 of the minute wheel, whereby rotation of the stem causes the hands to be set. Also in the first axial position, projections 16 on the stem are disengaged from the tabs 17 on the date setting member 7.

When the stem is pushed into a second or inner axial position A as shown in FIG. 1, key 30 is disposed in slot 31 so that the stem cannot easily rotate. In this position, the tabs 8 of the date setting member 7 are in the horizontal position shown in FIG. 6 and disengaged from the date ring 5 so that the day and date are advanced in the normal manner when the watch runs.

When it is desired to advance the date ring by one calendar date number, crown 3 is rotated in the proper direction. The key 30 in the stem slides on cam surfaces 32 on the stem bracket causing the stem to shift slightly to a third or intermediate axial position B. The bushing 14 and disk 7 are still coupled to the stem via projections 16 and tabs 17, but the stem pinion 24 is disengaged from minute wheel teeth 4. Continued rotation of the crown causes the date setting tabs 8 to engage the teeth 5a of the date ring. After one-half revolution the flexible spring arms 23 of the stern bracket urge the key 30 back into slot 31 to again lock the stem. The member 7, therefore, is only actuatable when the stem is in the intermediate position.

Thus an improved stem locking mechanism has been shown and it is desired to secure by the following claims all such modifications as fall within the true spirit and scope of the invention.

I claim:

1. In a watch of the type having a calendar ring with means for circumferentially advancing the ring from one position to the next during normal timekeeping and further having a time setting wheel with teeth and further having a rotatably mounted and axially slidable stem carrying a time setting pinion mounted for engagement with said time setting wheel in a first axial stem position, and also having a fixed stem bracket receiving one end of the stem and having means cooperating with the stem to hold it either in said first axial position or to urge it toward a second axial position where the time setting pinion is disengaged from the time setting wheel, the aforesaid elements being known in the art, the improvement comprising:

a date setting member adapted to be coupled to the stem and having at least one tab means thereon engageable with said calendar ring to advance it to a new circumferential position, said member further being disengageable from the stem when it is moved to said first axial position,

said stern having locking key means thereon and said stem-receiving portion of said stem bracket having an irregular aperture therein for receiving said locking key and preventing rotation when the stem is in said second axial position, and

cam means formed by the wall of said aperture to cause the stem to move to a third intermediate axial position without engaging the time setting wheel or disengaging the date setting member, whereby the date may be rapidly advanced by rotacam surfaces are provided by the walls of the aperture. l l= =l 

1. In a watch of the type having a calendar ring with means for circumferentially advancing the ring from one position to the next during normal timekeeping and further having a time setting wheel with teeth and further having a rotatably mounted and axially slidable stem carrying a time setting pinion mounted for engagement with said time setting wheel in a first axial stem position, and also having a fixed stem bracket receiving one end of the stem and having means cooperating with the stem to hold it either in said first axial position or to urge it toward a second axial position where the time setting pinion is disengaged from the time setting wheel, the aforesaid elements being known in the art, the improvement comprising: a date setting member adapted to be coupled to the stem and having at least one tab means thereon engageable with said calendar ring to advance it to a new circumferential position, said member further being disengageable from the stem when it is moved to said first axial position, said stem having locking key means thereon and said stemreceiving portion of said stem bracket having an irregular aperture therein for receiving said locking key and preventing rotation when the stem is in said second axial position, and cam means formed by the wall of said aperture to cause the stem to move to a third intermediate axial position without engaging the time setting wheel or disengaging the date setting member, whereby the date may be rapidly advanced by rotation of the date setting member.
 2. The combination according to claim 1, wherein said date setting member has diametrically opposed tabs and wherein said aperture is key hole shaped with diametrically opposed cam surfaces, whereby one half revolution of the stem advances the calendar ring by one position.
 3. The combination according to claim 1, wherein said stem bracket includes a base portion with diametrically opposed flexible spring arms, and wherein said aperture is cut in said base portion and wherein said cam surfaces are provided by the walls of the aperture. 